Motor vehicle transmission devices are known in various forms. Starting from conventional manual transmissions, automated manual transmissions (AMTs) for example were created, in which shifting processes are controlled (actuated) electronically. Furthermore, transmissions have become known which have parallel-shifted power train branches, for example double clutch transmissions (DCTs) or parallel shift transmissions (PSTs).
With motor vehicle transmission devices, a distinction is often made between the internal gearbox with its internal gear shifting system and an external gear shifting system, which is also often referred to as a transmission actuator—in particular in the case of designs supported by external force or designs with an electric motor.
The internal gearbox with its internal gear shifting system usually has the components that form the different transmission ratios, such as gear wheels, as well as components that are or can be coupled with these components, such as shafts. As a rule, gear clutches or devices of equivalent or similar function are provided here, by means of which linkages can be produced to engage gears and released to disengage gears. An example of this can be that by means of such a gear clutch a rotationally fixed connection can be created or released between a gear wheel of a gear set that produces one gear ratio and a shaft that carries that gear wheel. The internal gear shifting system extends from these gear clutches to the interface to the external gear shifting system. In most cases the latter has a plurality of mechanisms, which extend from a gear clutch in the direction of the external gear shifting system. A variety of designs are known in which in order to transmit power from the external gear shifting system to the internal gear shifting system these aforementioned mechanisms each have a shift gap or the like, which is inserted for example into a shift rail or shift fork or the like. The external gear system here frequently has one or more parts such as selector fingers, which these shift gaps can engage and activate. This is frequently realized in that to make a selection such a selector finger or the like can be moved into a position, out of which it can then be moved in an additional motion whose direction generally differs from the direction of the selecting motion, to perform the shift.
It is also known that in gear shifting processes in classically designed stepped transmission devices—starting from the former gear—the following three steps take place in time sequence: “Disengaging the former gear”- “selecting”- “engaging the destination gear.” In addition, motor vehicle transmission designs have become known in which the selecting or selection motions can take place before the former gear is disengaged. Such designs include the provision for example that a main operating element or selecting finger is essentially responsible only for engaging gears, and that additional geometries assume the function of disengaging gears. Here in particular so-called auxiliary operating elements are used for the disengaging function. It is also known that the additional geometries are located for example on the one hand on a central shifting shaft, and on the other hand on shift gaps which are provided on the forenamed mechanisms or final output mechanisms or shift forks or shift rails or the like.
As a rule the disengaging geometries work in tracks in which the selecting finger or some main operating element is not active. Provision may be made so that a firm assignment between selecting finger or main operating element and disengaging geometry simultaneously represents an active gear block. Design implementations of this approach are therefore also known as “active interlock.”
Such an “active interlock” generally provides that the main operating element or selecting finger can be moved back into the middle or neutral position even with a gear engaged, without disengaging the gear. The selecting movement becomes possible here before the gear is disengaged.
Examples of such designs are explained for instance in the Applicant's DE 102 06 561 A1.
Where gear changing processes in the designs of the forenamed type are controlled electronically by means of an electric motor, these designs always have two separate electric motors. The first of these electric motors, known as the selector motor, serves to select gears, and the second electric motor, known as the shift motor, serves to shift or engage gears.
In addition, however, a design has become known in which the gear shifting processes can be controlled in principle with only one electric motor. In this design, which is evaluated for example in the descriptive introduction of DE 102 06 561 A1, the operating device of the motor vehicle transmission device has a so-called selector drum, which is situated so that it can rotate and in whose outer jacket there are curtain-like grooves. The internal gear shifting system or final output mechanisms, each having a shift fork, are operated in this design by means of the selector drum. To this end elements coupled with the shift forks engage the curtain-like grooves; as the selector drum rotates they slide into these curtain-like grooves in such a way that their coupling with the shift forks and the latter's coupling with gear clutches brings about gear change processes. In this design the shifting sequence of the gear ratio steps or gears is determined by the design of the grooves.